reflex-dev/reflex · error · ValueError

Match condition {condition_index} of case {case_index} canno

Error message

Match condition {condition_index} of case {case_index} cannot be a component.

What it means

In rx.match, conditions (all tuple elements except the last) must be vars or values convertible to vars, not components. Components are only allowed as the return value (last element) of a case.

Source

Thrown at packages/reflex-components-core/src/reflex_components_core/core/match.py:167

            The processed match cases.

        Raises:
            ValueError: If the default case is not the last case or the tuple elements are less than 2.
        """
        match_cases: list[tuple[list[Var], BaseComponent | Var]] = []
        for case_index, case in enumerate(cases):
            # There should be at least two elements in a case tuple(a condition and return value)
            if len(case) < 2:
                msg = "A case tuple should have at least a match case element and a return value."
                raise ValueError(msg)

            *conditions, return_value = case

            conditions_vars: list[Var] = []
            for condition_index, condition in enumerate(conditions):
                if isinstance(condition, BaseComponent):
                    msg = f"Match condition {condition_index} of case {case_index} cannot be a component."
                    raise ValueError(msg)
                conditions_vars.append(cls._create_case_var_with_var_data(condition))

            return_value = (
                cls._create_case_var_with_var_data(return_value)
                if not isinstance(return_value, BaseComponent)
                else return_value
            )

            if not isinstance(return_value, (Var, BaseComponent)):
                msg = "Return value must be a var or component"
                raise ValueError(msg)

            match_cases.append((conditions_vars, return_value))

        return match_cases

    @classmethod
    def _validate_return_types(

View on GitHub (pinned to 45b8ed5ab7)

Solutions

1. Reorder so the component is the last element: (condition, component_return_value)
2. If the condition must render something, compute it as a var (e.g. a computed var or expression) instead of a component

Example fix

# before
rx.match(State.n, (rx.text("one"), 1))
# after
rx.match(State.n, (1, rx.text("one")))

from reflex.components.base.bare import Bare
from reflex.components import Component

conditions = case[:-1]
assert not any(isinstance(c, Component) for c in conditions), 'conditions cannot be components'

def has_component_condition(case: tuple) -> bool:
    return any(isinstance(c, Component) for c in case[:-1])

When it happens

Trigger: Passing a component as a non-final tuple element, e.g. rx.match(cond, (rx.text("a"), rx.text("b"))) where the first rx.text is treated as a condition rather than a return value.

Common situations: Miscounting tuple positions: intending (return_value, condition) order, or forgetting that only the last element is the return value when a case has one condition.

Related errors

• For cases with return types as Vars, a default case must be
• The condition must be set
• rx.match should have at least one case.
• rx.match should have tuples of cases and one default case as
• A case tuple should have at least a match case element and a

AI-assisted analysis of reflex-dev/reflex@45b8ed5ab7 (2026-08-28). Data as JSON: /api/errors/bca3fee060511400. Report an issue: GitHub.